Question with "beginning at your end step" and sacrificing creatures

So, let's say I have [[Carrion Feeder]] [[Prized Amalgam]] and [[Gravecrawler]] in my deck. With carrion feeder and Gravecrawler I already have a loop of sacrificing for tokens and returning Gravecrawler to the battlefield from the graveyard. Now, prized Amalgam returns at the beginning of my end step tapped. Does that mean that during my end step, I could sacrifice Prized Amalgam, then Gravecrawler, have Gravecrawler return from Graveyard for 1 mana and with it prized Amalgam, rinse and repeat, or is that not allowed during the end step?